Auto Detect URL in Text Then Make Clickable

PHP Code To Auto Detect URL in Text Then Make Clickable

This function can auto detect URL in  all text, then make the URL clickable. Here the code:

function autolink( &$text, $target='_blank', $nofollow=true )
{
  // grab anything that looks like a URL...
  $urls  =  _autolink_find_URLS( $text );
  if( !empty($urls) ) // i.e. there were some URLS found in the text
  {
    array_walk( $urls, '_autolink_create_html_tags', array('target'=>$target, 'nofollow'=>$nofollow) );
    $text  =  strtr( $text, $urls );
  }
}

function _autolink_find_URLS( $text )
{
  // build the patterns
  $scheme         =       '(http:\/\/|https:\/\/)';
  $www            =       'www\.';
  $ip             =       '\d{1,3}\.\d{1,3}\.\d{1,3}\.\d{1,3}';
  $subdomain      =       '[-a-z0-9_]+\.';
  $name           =       '[a-z][-a-z0-9]+\.';
  $tld            =       '[a-z]+(\.[a-z]{2,2})?';
  $the_rest       =       '\/?[a-z0-9._\/~#&=;%+?-]+[a-z0-9\/#=?]{1,1}';            
  $pattern        =       "$scheme?(?(1)($ip|($subdomain)?$name$tld)|($www$name$tld))$the_rest";
    
  $pattern        =       '/'.$pattern.'/is';
  $c              =       preg_match_all( $pattern, $text, $m );
  unset( $text, $scheme, $www, $ip, $subdomain, $name, $tld, $the_rest, $pattern );
  if( $c )
  {
    return( array_flip($m[0]) );
  }
  return( array() );
}

function _autolink_create_html_tags( &$value, $key, $other=null )
{
  $target = $nofollow = null;

  if(stripos($key, "http")===FALSE){ $key="http://".$key;}

  if( is_array($other) )
  {
    $target      =  ( $other['target']   ? " target=\"$other[target]\"" : null );
    $nofollow    =  ( $other['nofollow'] ? ' rel="nofollow"'            : null );     
  }
  $value = "<a title=\"Modify your prefer title\" href=\"$key\"$target$nofollow>$key</a>";
} 

$text = "this is a link to http://www.google.com/";
autolink($text);
echo $text;

Good Luck !!!